Temperature-responsive microcapsules alleviating the hazards of thermal runaway for lithium-ion batteries

Safety problems hinder the large-scale application of high-specific energy battery system. In this paper, a type of temperature thermo-responsive microcapsules to enhance the safety performance of lithium-ion batteries is proposed. The microcapsule is manufactured by encapsulating hydrates with melamine urea formaldehyde, and the outer shell will automatically rupture and release hydrates at ∼100 °C. It can react with the anode in advance and block reaction between the anode and the electrolyte, thereby reducing the generation of reductive gas and lowering down gas crosstalk. The thermos-responsive microcapsules are prepared by in situ polymerization, and the addition of the microcapsules could effectively reduce the reaction enthalpy by differential scanning calorimetry. Through a adiabatic accelerated calorimetry test, only 0.25 g microcapsules can increase the thermal runaway trigger temperature by 16.2 °C and reduce the maximum temperature by 117.5 °C. This innovative approach enhances the safety of high specific energy lithium-ion battery systems, providing extended thermal-runaway warning time and minimizing the hazard caused by high temperatures.